1. Field of Invention
The present disclosure relates to hydraulic fracturing operations in a subterranean formations. In particular, the present disclosure relates to a hydraulic fracturing system with imaging devices that are strategically positioned to remotely monitor portions of the system.
2. Description of Prior Art
Hydraulic fracturing is a technique used to stimulate production from some hydrocarbon producing wells. The technique usually involves injecting fluid into a wellbore at a pressure sufficient to generate fissures in the formation surrounding the wellbore. Typically the pressurized fluid is injected into a portion of the wellbore that is pressure isolated from the remaining length of the wellbore so that fracturing is limited to a designated portion of the formation. The fracturing fluid slurry, whose primary component is usually water, includes proppant (such as sand or ceramic) that migrate into the fractures with the fracturing fluid slurry and remain to prop open the fractures after pressure is no longer applied to the wellbore. A primary fluid for the slurry other than water, such as nitrogen, carbon dioxide, foam (nitrogen and water), diesel, or other fluids is sometimes used as the primary component instead of water. Typically hydraulic fracturing fleets include a data van unit, blender unit, hydration unit, chemical additive unit, hydraulic fracturing pump unit, sand equipment, and other equipment.
The process of making the fracturing fluid slurry necessarily includes combining, such as in the blender, hydration unit, chemical additive unit, etc., the individual components of the slurry. Such operation can be dangerous to operating personnel. For example, moving proppant into the blender unit can generate silica dust which, if inhaled by personnel, can cause permanent damage to the lungs. Common proppant types include silica sand, resin coated sand, and ceramic beads. Ceramic can be very harmful to inhale, and typically consists of very fine particles that become airborne and are difficult to filter out. Resin coated sand is the most dangerous and harmful to inhale since the resin coating can chip off and become airborne dust particles. Silica itself is very harmful to inhale as well.
Other components, such as chemicals, can be damaging and present hazards as well. One dangerous source of chemical contact comes from residue on tankers, trailer decks, reused hoses and camlock fittings, or leaky valves. In addition, there is always a risk for a major hose or chemical pump failure, or a tank/tote puncture. Some chemicals (such as, for example the viscosifier guar gel, and some friction reducers) can be hazardous because of how slick and slippery they are. Thus, a small amount on the skin, clothing, ground, or equipment can cause personnel to slip and fall, or lose their grip while climbing ladders, leading to injuries.
In addition, chemicals such as acids and breakers (for breaking down viscosifiers) are extremely corrosive to skin, damaging to inhale, can cause blindness, and other immediate hazards. Chemicals such as breakers are also very flammable, which becomes a hazard if there is a chance of contact with, for example, diesel fuel or gasoline. On diesel powered fracturing sites, it is very common for personnel to have diesel or oil residue on their hands, boots, or clothes.
Furthermore, in fracturing operations, it is also common to use biocides to kill bacteria deep in a well, such as to prevent deadly hydrogen sulfide gas build up. Biocides can be very damaging to living tissue, especially if ingested or inhaled. Additional chemicals that are dangerous if ingested or inhaled include stabilizers, pH buffers, and inhibitors.
In addition to the above, hydraulic fracturing operations can be dangerous for operating personnel because of high pressure and high voltage equipment. For example, high pressure zones are present where the discharge piping leaves the hydraulic fracturing pumps at pressures of up to 15,000 pounds per square inch (psi) or more. If the pipes fail, they can explode, causing shrapnel to fly. Furthermore, iron pipes can shift and pivot with the pressure release striking employees.
Some voltages in the electric hydraulic fracturing systems can reach up to 13,800 volts or more. Dangers in high voltage zones include arc flashes, fires, electrocution, and explosions. Hazards can result from breaker or cable coupler failures, or even natural gas vapors entering the area. It is desirable, therefore, to design a hydraulic fracturing system to minimize such dangerous exposure of operating personnel.